Adjudication of Transient Ischemic Attack and Stroke in the Multi-Ethnic Study of Atherosclerosis

Background: To describe adjudication of transient ischemic attack (TIA) and stroke in an observational study. Methods: We detail the process used to adjudicate TIA and stroke in the Multi-Ethnic Study of Atherosclerosis (MESA), a large longitudinal cohort study. Two of three vascular neurologists adjudicated each event using specific protocols. We examined the initial agreement, effect of imaging on diagnosis of TIA versus ischemic stroke, and effect of strict and less strict criteria on the number of ischemic stroke subtypes classified as undetermined. Results: Of 573 adjudicated events over 13.5 years of follow-up, 95 (16.5%) had TIA and 269 (47.0%) had stroke: 211 (78.4%) ischemic, 43 (16.0%) hemorrhagic, and 15 (5.6%) other. Disagreements occurred on 16% of initial adjudication of events. Using results from imaging, the number with TIA decreased by 8.6% and with ischemic stroke increased by 4.1%. Using less strict criteria to classify ischemic stroke subtypes reduced the number classified as undetermined, from 137 to 59, and numbers classified as cardioembolic and small vessel doubled. Conclusions: We hope that this work will motivate and facilitate investigators to use MESA data to investigate issues concerning TIA and stroke and will inform investigators seeking to adjudicate TIA and stroke in other studies.